Preheat your oven to 350°F (175°C) and line a muffin tin with cupcake liners.

Cream together softened unsalted butter and granulated sugar until light and fluffy. Add eggs one at a time, then stir in vanilla extract, instant espresso powder, and cooled brewed espresso.

Mix all-purpose flour, cocoa powder, baking powder, baking soda, and salt in a separate bowl.

Gradually add the dry mix to the wet mixture, mixing until just combined.

Spoon the batter into cupcake liners, filling about two-thirds full, and bake for 16–18 minutes until done. Let cool.

Beat softened unsalted butter until fluffy, then gradually add powdered sugar, mixing until combined. Add instant espresso powder and brewed espresso, mixing until smooth.

Frost the cooled cupcakes with the espresso frosting using a piping bag and garnish if desired.